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Mijakoski D, Cheptea D, Marca SC, Shoman Y, Caglayan C, Bugge MD, Gnesi M, Godderis L, Kiran S, McElvenny DM, Mediouni Z, Mesot O, Minov J, Nena E, Otelea M, Pranjic N, Mehlum IS, van der Molen HF, Canu IG. Determinants of Burnout among Teachers: A Systematic Review of Longitudinal Studies. Int J Environ Res Public Health 2022; 19:ijerph19095776. [PMID: 35565168 PMCID: PMC9104901 DOI: 10.3390/ijerph19095776] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 12/03/2022]
Abstract
We aimed to review the determinants of burnout onset in teachers. The study was conducted according to the PROSPERO protocol CRD42018105901, with a focus on teachers. We performed a literature search from 1990 to 2021 in three databases: MEDLINE, PsycINFO, and Embase. We included longitudinal studies assessing burnout as a dependent variable, with a sample of at least 50 teachers. We summarized studies by the types of determinant and used the MEVORECH tool for a risk of bias assessment (RBA). The quantitative synthesis focused on emotional exhaustion. We standardized the reported regression coefficients and their standard errors and plotted them using R software to distinguish between detrimental and protective determinants. A qualitative analysis of the included studies (n = 33) identified 61 burnout determinants. The RBA showed that most studies had external and internal validity issues. Most studies implemented two waves (W) of data collection with 6–12 months between W1 and W2. Four types of determinants were summarized quantitatively, namely support, conflict, organizational context, and individual characteristics, based on six studies. This systematic review identified detrimental determinants of teacher exhaustion, including job satisfaction, work climate or pressure, teacher self-efficacy, neuroticism, perceived collective exhaustion, and classroom disruption. We recommend that authors consider using harmonized methods and protocols such as those developed in OMEGA-NET and other research consortia.
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Affiliation(s)
- Dragan Mijakoski
- Institute of Occupational Health of RNM, WHO Collaborating Center, 1000 Skopje, North Macedonia;
- Faculty of Medicine, Ss. Cyril and Methodius, University in Skopje, 1000 Skopje, North Macedonia
- Correspondence:
| | - Dumitru Cheptea
- Faculty of Medicine and Pharmacy, Nicolae Testemitanu State University of Medicine and Pharmacy, 2004 Chisinau, Moldova;
| | - Sandy Carla Marca
- Center of Primary Care and Public Health (Unisanté), University of Lausanne, 1066 Epalinges-Lausanne, Switzerland; (S.C.M.); (Y.S.); (Z.M.); (O.M.); (I.G.C.)
| | - Yara Shoman
- Center of Primary Care and Public Health (Unisanté), University of Lausanne, 1066 Epalinges-Lausanne, Switzerland; (S.C.M.); (Y.S.); (Z.M.); (O.M.); (I.G.C.)
| | - Cigdem Caglayan
- Department of Public Health, Faculty of Medicine, Kocaeli University, İzmit 41001, Turkey;
| | - Merete Drevvatne Bugge
- National Institute of Occupational Health (STAMI), 0363 Oslo, Norway; (M.D.B.); (I.S.M.)
| | - Marco Gnesi
- Department of Public Health, Experimental and Forensic Medicine, University of Pavia, 27100 Pavia, Italy;
| | - Lode Godderis
- Department of Primary Care and Public Health, University of Leuven, 3000 Leuven, Belgium;
| | - Sibel Kiran
- Department of Occupational Health and Safety, Institute of Public Health, Hacettepe University, Ankara 06100, Turkey;
| | - Damien M. McElvenny
- Research Group, Institute of Occupational Medicine, Edinburgh EH14 4AP, UK;
- Centre for Occupational and Environmental Health, University of Manchester, Manchester M13 9PL, UK
| | - Zakia Mediouni
- Center of Primary Care and Public Health (Unisanté), University of Lausanne, 1066 Epalinges-Lausanne, Switzerland; (S.C.M.); (Y.S.); (Z.M.); (O.M.); (I.G.C.)
| | - Olivia Mesot
- Center of Primary Care and Public Health (Unisanté), University of Lausanne, 1066 Epalinges-Lausanne, Switzerland; (S.C.M.); (Y.S.); (Z.M.); (O.M.); (I.G.C.)
| | - Jordan Minov
- Institute of Occupational Health of RNM, WHO Collaborating Center, 1000 Skopje, North Macedonia;
- Faculty of Medicine, Ss. Cyril and Methodius, University in Skopje, 1000 Skopje, North Macedonia
| | - Evangelia Nena
- Medical School, Democritus University of Thrace, 68100 Alexandroupolis, Greece;
| | - Marina Otelea
- Clinical Department 5, Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania;
| | - Nurka Pranjic
- Department of Occupational Medicine, School of Medicine, University of Tuzla, 75000 Tuzla, Bosnia and Herzegovina;
- Clinic of Occupational Pathology and Toxicology, University Institute of Primary Health, 75000 Tuzla, Bosnia and Herzegovina
| | - Ingrid Sivesind Mehlum
- National Institute of Occupational Health (STAMI), 0363 Oslo, Norway; (M.D.B.); (I.S.M.)
- Institute of Health and Society, University of Oslo, 0373 Oslo, Norway
| | - Henk F. van der Molen
- Amsterdam UMC Location University of Amsterdam, Public and Occupational Health, Netherlands Center for Occupational Diseases, Meibergdreef 9, 1100 DD Amsterdam, The Netherlands;
- Amsterdam Public Health Research Institute, Societal Participation & Health, 1105 BP Amsterdam, The Netherlands
| | - Irina Guseva Canu
- Center of Primary Care and Public Health (Unisanté), University of Lausanne, 1066 Epalinges-Lausanne, Switzerland; (S.C.M.); (Y.S.); (Z.M.); (O.M.); (I.G.C.)
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Bugge MD. Health effects of RCS exposure - reduced OEL. Saf Health Work 2022. [DOI: 10.1016/j.shaw.2021.12.787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Mehlum IS, Albin M, Bugge MD, Burdorf A, Castaño G, Kogevinas M, Kolstad H, Lucas R, McElvenny D, Pearce N, Peters S, Schlünssen V, Vermeulen R, Turner MC. Network on the Coordination and Harmonisation of European Occupational Cohorts (OMEGA-NET): Achievements after 4 years of networking, collaboration and training. Saf Health Work 2022. [DOI: 10.1016/j.shaw.2021.12.1141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Molander P, Bast-Pettersen R, Nordby KC, Bugge MD. Gunnar Mowé. Tidsskriftet 2021. [DOI: 10.4045/tidsskr.21.0574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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Guseva Canu I, Mesot O, Györkös C, Mediouni Z, Mehlum IS, Bugge MD. Burnout syndrome in Europe: towards a harmonized approach in occupational health practice and research. Ind Health 2019; 57:745-752. [PMID: 30814391 PMCID: PMC6885602 DOI: 10.2486/indhealth.2018-0159] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 01/29/2019] [Indexed: 06/09/2023]
Abstract
Health practitioners and decision makers in the medical and insurance systems need knowledge on the work-relatedness of burnout. To gather the most reliable information regarding burnout diagnosis and recognition in Europe, we used an 8-item standard questionnaire sent by e-mail to occupational health specialists identified via the Network on the Coordination and Harmonization of European Occupational Cohorts (OMEGA-NET) within the European Cooperation in Science and Technology (COST) Action. Participation rate was 100%, and the questionnaire was completed for 37 countries. In 14 (38%) countries burnout syndrome can be acknowledged as an occupational disease. However, only one country included burnout on the list of occupational diseases. The results showed a high variability in burnout diagnosis, in assessment of its work-relatedness, and in conditions allowing compensation of patients. These results reflect a lack of graded evidence on burnout and its determinants. The ongoing research on burnout conducted in the frame of the OMEGA-NET COST Action should be helpful through facilitating standardization of both existing and new data on burnout, a priority outcome requiring harmonization.
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Affiliation(s)
- Irina Guseva Canu
- Center for primary care and public health (Unisanté), University of Lausanne, Switzerland
| | - Olivia Mesot
- Center for primary care and public health (Unisanté), University of Lausanne, Switzerland
| | - Christina Györkös
- Center for primary care and public health (Unisanté), University of Lausanne, Switzerland
| | - Zakia Mediouni
- Center for primary care and public health (Unisanté), University of Lausanne, Switzerland
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Bugge MD, Ulvestad B, Berlinger B, Stockfelt L, Olsen R, Ellingsen DG. Reactive hyperemia and baseline pulse amplitude among smelter workers exposed to fine and ultrafine particles. Int Arch Occup Environ Health 2019; 93:399-407. [PMID: 31773255 PMCID: PMC7078172 DOI: 10.1007/s00420-019-01491-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 11/15/2019] [Indexed: 11/24/2022]
Abstract
Objective Ambient exposure to fine particles is associated with increased cardiovascular morbidity and mortality. Associations between occupational particulate matter (PM) exposure and cardiovascular disease have been studied less. The objective of this study was to examine associations between PM exposure and endothelial function among workers in Norwegian smelters. Methods We examined endothelial function with Endo-PAT equipment after a working day (WD) and on a day off (DO) in 59 furnace workers recruited from three metal smelters in Norway. The difference in baseline pulse amplitude (BPA) and reactive hyperemia index (RHI) between the 2 days was analysed in relation to individual exposure to PM < 250 nm (PM250) or the respirable aerosol fraction of particles, and adjusted for relevant covariates. Results The exposure to PM250 ranged from 0.004 to 5.7 mg/m3. The mean BPA was significantly higher on WD relative to DO (772 vs. 535, p = 0.001). This difference was associated with PM concentrations among participants ≥ 34 years, but not among the younger workers. Reactive hyperemia was significantly lower on workdays relative to days off (1.70 vs. 1.84, p = 0.05). This difference was observed only among participants above the age 34. No associations with PM exposure were observed. Conclusions PM exposure was associated with higher BPA among participants older than 34 years. BPA reflects microvessel pulsatility. Our results may indicate an age-dependent cardiovascular susceptibility to PM exposure. Endothelial function measured by RHI was reduced on WD among participants 34 years and older, but we found no associations between PM exposure and RHI.
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Affiliation(s)
| | - B Ulvestad
- National Institute of Occupational Health, Oslo, Norway
| | - B Berlinger
- National Institute of Occupational Health, Oslo, Norway
| | - L Stockfelt
- Unit of Occupational and Environmental Medicine, Department of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - R Olsen
- National Institute of Occupational Health, Oslo, Norway
| | - D G Ellingsen
- National Institute of Occupational Health, Oslo, Norway
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Berlinger B, Bugge MD, Ulvestad B, Kjuus H, Kandler K, Ellingsen DG. Particle size distribution of workplace aerosols in manganese alloy smelters applying a personal sampling strategy. Environ Sci Process Impacts 2015; 17:2066-2073. [PMID: 26498986 DOI: 10.1039/c5em00396b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Air samples were collected by personal sampling with five stage Sioutas cascade impactors and respirable cyclones in parallel among tappers and crane operators in two manganese (Mn) alloy smelters in Norway to investigate PM fractions. The mass concentrations of PM collected by using the impactors and the respirable cyclones were critically evaluated by comparing the results of the parallel measurements. The geometric mean (GM) mass concentrations of the respirable fraction and the <10 μm PM fraction were 0.18 and 0.39 mg m(-3), respectively. Particle size distributions were determined using the impactor data in the range from 0 to 10 μm and by stationary measurements by using a scanning mobility particle sizer in the range from 10 to 487 nm. On average 50% of the particulate mass in the Mn alloy smelters was in the range from 2.5 to 10 μm, while the rest was distributed between the lower stages of the impactors. On average 15% of the particulate mass was found in the <0.25 μm PM fraction. The comparisons of the different PM fraction mass concentrations related to different work tasks or different workplaces, showed in many cases statistically significant differences, however, the particle size distribution of PM in the fraction <10 μm d(ae) was independent of the plant, furnace or work task.
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Affiliation(s)
- B Berlinger
- Dept. of Chemical and Biological Working Environment, National Institute of Occupational Health, P.O. Box 8149 Dep. N-0033, Oslo, Norway.
| | - M D Bugge
- Dept. of Occupational Medicine and Epidemiology, National Institute of Occupational Health, P.O. Box 8149 Dep. N-0033, Oslo, Norway
| | - B Ulvestad
- Dept. of Occupational Medicine and Epidemiology, National Institute of Occupational Health, P.O. Box 8149 Dep. N-0033, Oslo, Norway
| | - H Kjuus
- Dept. of Occupational Medicine and Epidemiology, National Institute of Occupational Health, P.O. Box 8149 Dep. N-0033, Oslo, Norway
| | - K Kandler
- Technical University Darmstadt, Institute of Applied Geosciences Darmstadt, Schnittspahnstr. 9, 64287 Darmstadt, Germany
| | - D G Ellingsen
- Dept. of Chemical and Biological Working Environment, National Institute of Occupational Health, P.O. Box 8149 Dep. N-0033, Oslo, Norway.
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Johnsen HL, Bugge MD, Føreland S, Kjuus H, Kongerud J, Søyseth V. Dust exposure is associated with increased lung function loss among workers in the Norwegian silicon carbide industry. Occup Environ Med 2013; 70:803-9. [PMID: 23852098 DOI: 10.1136/oemed-2012-101068] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES To investigate the relationship between dust exposure and annual change in lung function among employees in Norwegian silicon carbide (SiC) plants using a quantitative job exposure matrix (JEM) regarding total dust. METHODS All employees, 20-55 years of age by inclusion (n=456), were examined annually for up to 5 years (1499 examinations). Spirometry was performed at each examination, and a questionnaire encompassing questions of respiratory symptoms, smoking status, job and smoking history, and present job held was completed. A JEM was constructed based on 1970 personal total dust exposure measurements collected during the study period. The association between lung function and total dust exposure was investigated using linear mixed models. RESULTS The annual change in forced expiratory volume (FEV) in one second per squared height, FEV1/height(2), per mg/m(3) increase in dust exposure was -2.3 (95% CI -3.8 to -0.79) (mL/m(2))×year(-1). In an employee of average height (1.79 m) and exposure (1.4 mg/m(3)) the estimated contribution to the annual change in FEV1 associated with dust was 10.4 mL/year. The annual change in FEV1/height(2) in current, compared with non-smokers was -1.9 (-7.2 to 3.4) (mL/m(2))×year(-1). The estimated overall annual decline in FEV1 among current and non-smokers in the highest exposed group was -91.2 (-124.3 to -58.1) (mL/m(2))×year(-1) and -49.0 (-80.2 to -17.8) (mL/m(2))×year(-1), respectively. CONCLUSIONS Dust exposure, expressed by a quantitative JEM, was found to be associated with an increased yearly decline in FEV1 in employees of Norwegian SiC plants.
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Affiliation(s)
- Helle Laier Johnsen
- Department of Occupational Medicine and Epidemiology, National Institute of Occupational Health, Oslo, Norway
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Bugge MD, Kjærheim K, Føreland S, Eduard W, Kjuus H. Lung cancer incidence among Norwegian silicon carbide industry workers: associations with particulate exposure factors. Occup Environ Med 2012; 69:527-33. [PMID: 22611173 PMCID: PMC3400144 DOI: 10.1136/oemed-2011-100623] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES An increased lung cancer risk associated with total dust exposure in the silicon carbide (SiC) industry has previously been reported. The aim of the present study was to examine the relative importance of specific exposure factors by using a comprehensive, historic job exposure matrix based on about 8000 measurements. METHODS Cumulative exposure to total and respirable dust, respirable quartz, cristobalite, and SiC particles and SiC fibres was assessed for 1687 long-term workers employed during 1913-2003 in the Norwegian SiC industry. Standardised incidence ratios for lung cancer, with follow-up during 1953-2008, were calculated stratified by cumulative exposure categories. Poisson regression analyses were performed using both categorised and log-transformed cumulative exposure variables. RESULTS The lung cancer incidence was about twofold increased at the highest level of exposure to each of the exposure factors (standardised incidence ratios 1.9-2.3 for all agents). Internal analyses showed associations between exposure level and lung cancer incidence for all investigated factors, but a significant trend only for total dust and cristobalite. In multivariate analyses, cristobalite showed the most consistent associations, followed by SiC fibres. CONCLUSIONS The results indicated that crystalline silica in the form of cristobalite was the most important occupational exposure factor responsible for lung cancer excess in the Norwegian SiC industry. SiC fibres seemed to have an additional effect.
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Føreland S, Bugge MD, Bakke B, Bye E, Eduard W. A novel strategy for retrospective exposure assessment in the Norwegian silicon carbide industry. J Occup Environ Hyg 2012; 9:230-241. [PMID: 22448628 DOI: 10.1080/15459624.2012.666189] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The objective was to construct a retrospective job-exposure matrix (JEM) for the Norwegian silicon carbide industry. More than 3300 historical total dust measurements were available (1967-2005); however, there were few measurements of other agents. Total dust measurements were therefore used as the basis for the JEM, and a novel method was developed to estimate exposure to other agents. Multiple linear regression models were developed to describe historical exposure to total dust. Exposure estimates were extrapolated backward to periods without exposure data by adjustments for process and work-hour related changes. An exposure assessment study was performed where total dust was sampled in parallel with fibers or respirable dust. The respirable dust was analyzed for the content of quartz, cristobalite, and silicon carbide. Mixed-effect models were developed to estimate the exposure to these agents from total dust exposure, plant, and job group. Exposure to asbestos and polycyclic aromatic hydrocarbons was assigned qualitatively. Multiple linear regression models of total dust described historical exposure best in the furnace department (R(2) (adj) = 0.49-0.74). Models in the other departments explained less variance (R(2) (adj) = 0.12-0.32). Exposure determinants and total dust explained a substantial proportion of the between- (70-100%) and within-worker (8.0-54%) variance in the mixed-effect models. The relative bias between available historical measurements and the estimated exposure to dust components varied between -39% (fiber) and 40% (quartz). However, corrections were not considered necessary due to limitations in the historical data. The component-specific metrices were sufficiently different from each other (r(Pearson) < 0.7), with the exception of total and respirable dust (r(Pearson) = 0.84) and total dust and cristobalite (r(Pearson) = 0.72), and will enable component-specific epidemiologic analyses in the future. Improved and less correlated estimates of exposure levels for the different components in the dust were obtained with the updated exposure assessment. Due to limitations in the measurement data, assumptions had to be made, especially in the period before 1967. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a file containing tables outlining multiple linear regression models for prediction of total dust exposure in the processing departments of Norwegian SiC producing plants, evaluation of the predictive abilities of the reduced total dust models, and mixed models for pedicting exposure to fibers and respirable quartz, cristobalite, non-fibrous silicon carbide and respirable dust from total dust exposure.].
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Søyseth V, Johnsen HL, Bugge MD, Hetland SM, Kongerud J. Incidence of airflow limitation among employees in Norwegian smelters. Am J Ind Med 2011; 54:707-13. [PMID: 21360726 DOI: 10.1002/ajim.20946] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2011] [Indexed: 11/11/2022]
Abstract
We have investigated the association between the incidence of airflow limitation and occupational exposure. The employees (n = 3,924) were investigated annually during five years (n = 16,570) using spirometry. Exposure was classified using job category and a job exposure matrix. Airflow limitation was expressed using two indices: (i) as forced expiratory volume in one second/force vital capacity (FEV(1) /FVC) <0.7 and (ii) lower limit of normal (LLN). The incidence of airflow limitation was 21.2/1000 years(-1) and 15.1/1000 years(-1) using the fixed limit (0.7) and the LLN criterion, respectively. We found a dose-response relationship between the incidence of airflow limitation and tobacco consumption and with job-category in non-smokers. The associations between airflow limitation and covariates were independent of how airflow limitation was defined. The incidence of airflow limitation defined as FEV(l) /FVC <0.7 yielded higher incidence rates of airflow limitation than LLN. We found a significant association between the incidence of airflow limitation and occupational exposure in non-smokers.
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Affiliation(s)
- Vidar Søyseth
- Department of Medicine, Faculty Division Akershus University Hospital, University of Oslo, Lørenskog, Norway.
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Søyseth V, Johnsen HL, Bugge MD, Kongerud J. The association between symptoms and exposure is stronger in dropouts than in non-dropouts among employees in Norwegian smelters: a five-year follow-up study. Int Arch Occup Environ Health 2011; 85:27-33. [PMID: 21445648 PMCID: PMC3249535 DOI: 10.1007/s00420-011-0631-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 03/10/2011] [Indexed: 12/02/2022]
Abstract
Purpose We have investigated the association between respiratory symptoms and dust exposure among employees in 18 Norwegian smelters using a longitudinal design. Methods All employees (N = 3,084) were examined annually for 5 years (12,996 health examinations). At each examination, the subjects reported if they had respiratory symptoms, coded as 1 (yes) or 0 (no), on a respiratory questionnaire. Symptom score was constructed as the sum of symptoms (0–5). Full-time workers in the production line were classified as line operators; subjects never exposed in the production line were regarded as non-exposed. The remaining individuals were classified as non-line operators. A job-exposure matrix regarding dust exposure was also available. Analyses of repeated measurements were performed using generalised linear mixed model with log-link (Poisson regression). Adjustments were made for overdispersion. Results The mean age at inclusion was 39.0 years, and 89% were men. The median dust exposure in tertiles 1–3 was 0.19, 1.76 and 3.47 mg/m3. The longitudinal analyses showed that the association between symptoms-score ratio (SSR) and job category was significantly stronger in dropouts compared with non-dropouts (p = 0.01). Among the dropouts, SSR was 1.61 (95% confidence interval: 1.27–2.05) and 1.39 (1.09–1.77) in line operators and non-line operators compared with non-exposed employees, respectively. The corresponding SSR for subjects who completed the study was 1.13 (1.01–1.27) and 1.12 (1.00–1.26), respectively. Similarly, among the dropouts, the SSR between the second and the first tertile was 1.28 (1.05–1.55) and 1.37 (1.13–1.66) between the third tertile and the first tertile. Conclusions Line operators had more respiratory symptoms than non-exposed employees. This effect was significantly stronger in dropouts than in those who continued their jobs, indicating that there is a selection of subjects without respiratory symptoms in this industry.
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Affiliation(s)
- Vidar Søyseth
- Department of Medicine, Faculty Division Akershus University Hospital, University of Oslo, 1478, Lørenskog, Norway.
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Bugge MD, Føreland S, Kjærheim K, Eduard W, Martinsen JI, Kjuus H. Mortality from non-malignant respiratory diseases among workers in the Norwegian silicon carbide industry: associations with dust exposure. Occup Environ Med 2011; 68:863-9. [PMID: 21364203 PMCID: PMC3212646 DOI: 10.1136/oem.2010.062836] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Objectives Increased mortality from asthma, chronic bronchitis and emphysema has previously been reported among workers in the silicon carbide (SiC) industry. The objective of the present study was to evaluate the influence of specific exposure factors on mortality from obstructive lung diseases (OLD), using a newly revised job-exposure matrix. Materials and methods 1687 long-term workers employed in 1913–2003 in the Norwegian SiC industry were characterised with respect to cumulative exposure to quartz, cristobalite, SiC particles and SiC fibres. Standardised mortality ratios (SMRs) for underlying causes of death, 1951–2007, were calculated stratified by category of cumulative exposure, and Poisson regression analyses of OLD were performed using cumulative exposure variables. Results An increased total mortality (SMR 1.1, 95% CI 1.0 to 1.2) and increased mortality from cancer, non-malignant respiratory diseases and external factors, were observed. The SMR of OLD was increased at the highest level of cumulative exposure to all investigated exposure factors. In the internal analyses, a twofold increased risk of OLD was observed with increasing levels of cumulative exposure to SiC particles. In a multivariate model, SiC particles showed the most stable increased risk estimate when controlled for other exposure factors, among workers with less than 15 years of employment. Among workers with more than 15 years of employment, crystalline silica, primarily cristobalite, seemed to be the most important exposure factor. Conclusion Exposure to SiC and crystalline silica may contribute to OLD development among SiC industry workers in different time windows, and possibly through different mechanisms.
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Affiliation(s)
- Merete Drevvatne Bugge
- Department of Occupational Medicine and Epidemiology, National Institute of Occupational Health, Oslo, Norway.
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Bugge MD, Kjuus H, Martinsen JI, Kjærheim K. Cancer incidence among short- and long-term workers in the Norwegian silicon carbide industry. Scand J Work Environ Health 2009; 36:71-79. [PMID: 19953212 DOI: 10.5271/sjweh.2875] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVES A previous study among workers in the Norwegian silicon carbide industry, followed until 1996, revealed an excess incidence of lung and total cancer. The present study adds nine years of follow-up and focuses on cancer risk among short- and long-term workers, based on the assumption that these two groups have different exposure and lifestyle characteristics. METHODS The total cohort for this study comprised 2612 men employed for >6 months between 1913 and 2003. The follow-up period for cancer was 1953-2005. Short-term workers were defined as having <3 years of total employment in the industry. We estimated standardized incidence ratios (SIR) using national rates as the expected values. RESULTS Among the short-term workers, we observed an overall excess incidence of cancer [SIR 1.4, 95% confidence interval (95% CI) 1.2-1.6], with an excess of lung cancer (SIR 2.6, 95% CI 1.9-3.5) as the most important contributing factor. The long-term workers also had an excess incidence of total cancer (SIR 1.2, 95% CI 1.1-1.3) and lung cancer (SIR 1.7, 95% CI 1.3-2.2). We also observed an increased risk of cancers at other sites, specifically among short-term workers. CONCLUSIONS We observed an increased risk of cancer (especially in the lung but also at other sites) among both short- and long-term workers. Dust exposure in the silicon carbide industry may have contributed to the increased risk among long-term workers, whereas the increased risk among short-term workers may be due to a combination of occupational and lifestyle factors.
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